Lenticular lens sheets are elements to be used in a back-light unit of a liquid crystal display, a rear-projection display, a projection screen, a stereoscopic display, and the like. In general, a concave lens is formed like a stripe on a surface of a transparent substrate such as glass or a plastic sheet.
In particular, a three-dimensional display is known as one of the display systems which have attracted attention as next-generation display systems. Among modes of the three-dimensional display, as one which does not require any special glasses, a lenticular mode is typically given (see Non Patent Literature 1). Various three-dimensional displays of such mode in combination with a flat panel display such as a liquid crystal display (LCD) have recently been proposed, and thus the mode is considered to be closest to a practical level. However, in the conventional lenticular mode, an image resolution depends on a pitch of a lens or a barrier. Hence, a lens having a higher definition is required for realizing a display having a higher resolution. Further, it is necessary to position a lens and a barrier accurately with respect to a flat panel display.
Meanwhile, a three-dimensional display using a field-sequential light direction control back light has recently been proposed as a novel mode of the three-dimensional display (see Patent Literature 1). A principle of this mode involves adopting, as a back light of a display, a field-sequential light direction control back light 1 which can change a direction of light (LD) from the back light sequentially at high speed, and displaying an image depending on the direction of the light on a transmission display 2. Through utilization of this mode, binocular parallax images are provided in directions of left and right eyes LE and RE, and the directions are switched at blinding speed, thereby being able to provide a three-dimensional image to an observer. Further, an image resolution of this mode is the same as that of an LCD, and hence a high resolution of the LCD can be directly utilized, which facilitates manufacture and an increase in resolution.
In general, the lenticular lens has a spherical surface profile, and the following methods are known as processing means therefor. That is, for example, there are given: (1) a method of subjecting a molten or semi-molten thermoplastic resin to injection molding; (2) a method of subjecting a sheet to embossing under heating (see Patent Literature 2); (3) a method of curing an ultraviolet curable resin in a template with ultraviolet light (see Patent Literature 3); and (4) a method of subjecting an ultraviolet curable resin to screen printing, and curing the ultraviolet curable resin with ultraviolet light (see Patent Literature 4). However, any of these manufacturing methods requires a mold having high processing accuracy or requires a printing plate. Further, the mold or the plate inevitably comes into contact with a lens surface, and hence a foreign matter is mixed into a lens, or a flaw in the mold easily affects the lens.
Meanwhile, as a method of manufacturing a color filter by using an inkjet method, there is known a pixel forming method of spraying and curing inks of red, blue, and green only on required pixels, respectively, in a simultaneous manner, in which a partition is formed in advance in a photolithography process and the ink is ejected on a pixel portion defined by the partition. In this method, in order to avoid blurring of each color area and color mixing between adjacent areas, for example, an example is disclosed in Patent Literature 5 in which the color mixing can be avoided so long as a static contact angle between the ink and the partition surface is 40° to 55°. A height of the ink filled by using the inkjet method at this time with respect to a height of the partition is as high as about 4 times to 6 times.
As means for providing the partition to achieve such an object, the following two methods have been proposed. That is, (1) a treatment of a surface layer of the partition by using a fluorine-containing plasma gas (see Patent Literature 6) and (2) a method of mixing a fluorine-based compound or a silicon-based compound in a composition of a photoresist as a component for providing ink-repellency (see Patent Literature 5).
However, as for the manufacture of the color filter by using the inkjet method, although a resolution and a precision at a liquid crystal display device (LCD) level has already been established so far, there has been no attempt to manufacture a lenticular lens by using the inkjet method to the best of the inventors' knowledge despite the fact that a formation of a spherical dot lens by using the inkjet method is observed in some examples.